An interfacial uptake mechanism for the degradation of pyrene by a Rhodococcus strain
- 1 April 1997
- journal article
- Published by Microbiology Society in Microbiology
- Vol. 143 (4), 1087-1093
- https://doi.org/10.1099/00221287-143-4-1087
Abstract
The mechanism of uptake of polycyclic aromatic hydrocarbons (PAHs) was studied using a kinetic approach by electrolytic respirometry. In the case of the degradation of pyrene dissolved in a non-water-soluble non-degradable solvent (2,2,4,4,6,8,8-heptamethylnonane), by a Rhodococcus sp., two successive phases of exponential growth, during which over 80% of substrate degradation took place, were clearly characterized. During the second phase of biodegradation, rates of pyrene uptake were higher than those determined in abiotic conditions for the physicochemical transfer of pyrene from the solvent to the aqueous phase and no evidence for the presence of glycolipidic biosurfactants was obtained. The value of the specific growth rate for the first phase (𝜇max) was independent of the volume of the solvent phase and of the concentration of pyrene and was, in all cases, higher than that for the second phase (𝜇i). The 𝜇i values increased with the volume of the solvent phase but were independent of pyrene concentration, a clear indication of an interfacial uptake mechanism. The experimental kinetic data fitted well with a mathematical model incorporating PAH uptake both from the interface and from the aqueous medium by a population consisting of adsorbed cells in dynamic equilibrium with the cells in the aqueous medium, interfacial uptake being predominant in these experiments. Similar results were obtained for the degradation of fluoranthene. This newly demonstrated mechanism of PAH uptake is of great significance for the degradation of higher PAHs.Keywords
This publication has 16 references indexed in Scilit:
- Substrate availability in phenanthrene biodegradation: Transfer mechanism and influence on metabolismApplied Microbiology and Biotechnology, 1995
- Degradation of polycyclic aromatic hydrocarbons by pure strains and by defined strain associations: inhibition phenomena and cometabolismApplied Microbiology and Biotechnology, 1995
- Remediating tar-contaminated soils at manufactured gas plant sitesEnvironmental Science & Technology, 1994
- Biodegradation of polycyclic aromatic hydrocarbonsCurrent Opinion in Biotechnology, 1993
- Biodegradation of polycyclic aromatic hydrocarbonsBiodegradation, 1992
- Different modes of hydrocarbon uptake by two Pseudomonas speciesBiotechnology & Bioengineering, 1991
- PAH partitioning mechanisms with activated sludgeWater Research, 1989
- Determination of the solubility behavior of some polycyclic aromatic hydrocarbons in waterAnalytical Chemistry, 1978
- An interfacial kinetics model for hydrocarbons oxidationBiotechnology & Bioengineering, 1968
- Oxidative metabolism of naphthalene by soil pseudomonads. The ring-fission mechanismBiochemical Journal, 1964